Added a new routine kbdreset() to conduct a full keyboard reset.
Added definitions of all keyboard command codes and responces.
Replaced kbd_set_leds() with new function that used kbdcmd().
The keyboard attach function now detects whether a keyboard is
attached or not.
- split softc size and match/attach out from cfdriver into
a new struct cfattach.
- new "attach" directive for files.*. May specify the name of
the cfattach structure, so that devices may be easily attached
to parents with different autoconfiguration semantics.